caps wrapped in parentheses are missed

irb> require "redcloth"
irb> txt = "The Royal Society for Putting Things on Top of Other Things (RSFPTOTOOT)"
irb> RedCloth.new(txt).to_html
=> "<p>The Royal Society for Putting Things on Top of Other Things (RSFPTOTOOT)</p>"
Should be:
=> "<p>The Royal Society for Putting Things on Top of Other Things (<span class=\"caps\">RSFPTOTOOT</span>)</p>"